Flexible ceramic-metal insulation composite and method of making

Abstract

A method for joining a woven flexible ceramic fabric and a thin metal sheet creating an integral metal surfaced flexible thermal protection article, which method comprises: placing multiple dots of high temperature metallic or ceramic brazing material between the flexible ceramic fabric and the thin metal sheet in a random or organized pattern, with the proviso that the brazing material covers about 10% or less of the surface of one flat side of the metal sheet; heating the flexible ceramic fabric, brazing material and thin metal sheet for a predetermined period of time to integrally connect the same; and cooling the formed flexible article to ambient temperature. Preferably the flexible ceramic is selected from fibers comprising atoms of silicon, carbon, nitrogen, boron, oxygen or combinations thereof. The flexible thermal protection article produced is also part of the present invention. The thin metal sheet is comprised of titanium, aluminum, chromium, niobium or alloys or combinations thereof. The brazing material is selected from copper/silver or copper/gold or is a ceramic brazing or adhesive material.

We claim: 
     
       1. A method for joining a top surface of a woven flexible ceramic fabric structure which is filled with a ceramic insulation and a lower surface of a thin metal sheet which has an upper surface and a lower surface creating an integral metal surfaced flexible thermal protection article for use on the exterior surface of a space vehicle, which method comprises: a. placing a high temperature metallic or ceramic brazing material at multiple contact points located between and in contact with the surface of the woven flexible ceramic fabric structure which is filled with a ceramic insulation and the metal sheet;   b. heating the woven flexible ceramic fabric, ceramic insulation, brazing material, and metal sheet for a time to integrally connect the metal sheet, the braze, and the woven flexible ceramic fabric, which contains the ceramic insulation at the multiple contact points, with the proviso that the total surface area covered by the multiple contact points is about 10% or less of the total surface area of one flat surface of the metal sheet; and   c. cooling the formed integral metal surfaced flexible thermal protection article to ambient temperature, wherein said woven flexible ceramic fabric, ceramic insulation, brazing material, and metal sheet are heated between about 1,100° and 2,000° F.   
     
     
       2. The method of claim 1 wherein the thin metal sheet comprises titanium, aluminum, chromium, niobium, or combinations thereof. 
     
     
       3. The method of claim 1 wherein the brazing material is selected from copper/silver or copper/gold, each having either titanium or vanadium as wetting agents or ceramic brazing material comprising alumina. 
     
     
       4. The method of claim 1 wherein the brazing material is selected from copper/silver or a ceramic material comprising alumina, zirconia or SiO 2 . 
     
     
       5. The method of claim 1 wherein the woven flexible ceramic fabric is selected from fibers comprising silicon, carbon, nitrogen, boron, oxygen, aluminum or combinations thereof. 
     
     
       6. The method of claim 5 wherein the woven flexible ceramic fabric comprises silica, silicon carbide, aluminoborosilicate, silicon nitride, boron nitride, alumina or zirconia. 
     
     
       7. The method of claim 1 wherein the temperature of heating is between about 1,100° and 1,800° F. 
     
     
       8. The method of claim 7 wherein the thin metal sheet is between about 0.001 and 0.005 inches in thickness and comprises titanium, aluminum, chromium, niobium, or combinations thereof;   the woven flexible ceramic fabric is selected from ceramic fibers comprising silicon, carbon, boron, nitrogen, aluminum or combinations thereof; and   the brazing material is selected from copper/silver or copper/gold, each having titanium or vanadium as wetting agents, or from ceramics selected from alumina, zirconia or SiO 2 .   
     
     
       9. The method of claim 8 wherein the woven flexible ceramic fabric comprises silica, silicon carbide, aluminoborosilicate, silicon nitride, boron nitride, alumina or zirconia. 
     
     
       10. The method of claim 7 wherein the thin metal sheet comprises titanium, the flexible ceramic comprises silicon carbide, and   the brazing material is copper/silver having titanium as a wetting agent.   
     
     
       11. The integral metal sheet surfaced flexible thermal protection article produced by the method of claim 1. 
     
     
       12. The integral metal sheet surfaced flexible thermal protection article produced by the method of claim 6. 
     
     
       13. The integral metal sheet surfaced flexible thermal protection article produced by the method of claim 9. 
     
     
       14. An integral metal sheet surfaced flexible thermal protection article, which article comprises: a thin metallic sheet having an upper surface and a lower surface as a surface component;   a woven flexible ceramic fabric structure which is filled with a ceramic insulation; and   a multiplicity of high temperature metallic or ceramic contact points or contact lines of a brazing material which contact discrete separate regions of the lower surface of the metallic sheet and the woven flexible ceramic fabric structure and connecting the metallic sheet and ceramic fabric, with the proviso that the total surface area of the contact points or contact lines are about 10% or less of the total surface area of the lower surface of the metallic sheet.   
     
     
       15. The article of claim 14 wherein: the thin metallic sheet comprises titanium, aluminum, chromium, niobium, or combinations thereof.   
     
     
       16. The article of claim 14 wherein the woven flexible ceramic fabric structure comprises a ceramic of silicon, carbon, boron, nitrogen, aluminum or combinations thereof. 
     
     
       17. The article of claim 14 wherein the brazing material is selected from metal compositions of copper/silver with titanium or vanadium as a wetting agent or copper/gold with titanium or vanadium as a wetting agent, or from ceramic compositions selected from alumina, zirconia or SiO 2 . 
     
     
       18. The article of claim 17 wherein the thin metallic sheet comprises titanium, niobium or combinations thereof;   the woven flexible ceramic fabric is selected from fibers of silica, SiO 2 , alumina, silicon carbide, silicon nitride, aluminoborosilicate, or boron nitride; and   the brazing material is a metal composition.   
     
     
       19. The article of claim 18 wherein the metallic sheet comprises titanium, the woven flexible ceramic fabric is a ceramic selected from silica or silicon carbide, and,   the brazing material is copper/silver having titanium as a wetting agent.